Myringopexy type titanium prosthesis

ABSTRACT

A middle ear prosthesis comprises a one piece disk shaped prosthesis including a generally circular malleable body including a bore. The body engages a tympanic membrane and the bore receives a head of a stapes when implanted in a middle ear. More particularly, the middle ear prosthesis comprises a body comprising an annular head, a collar, and a plurality of radially extending members connecting the head to the collar. The head engages a tympanic membrane and the collar receives a head of a stapes when implanted in a middle ear.

FIELD OF THE INVENTION

This invention relates to an ossicular prosthesis used for replacementand reconstruction and, more particularly, to a myringopexy typeprosthesis.

BACKGROUND OF THE INVENTION

Due to disease, trauma, or congenital malformation, the ossicles of themiddle ear are sometimes damaged. Pexy is a medical term which generallyrefers to fixation. Myringo is a medical term generally referring to theear drum. Myringopexy is a condition where the ear drum becomes fixed tothe ossicles. More specifically, myringostapediopexy is a conditionwhere the eardrum is fixed to the stapes with the stapes acting like acolumella. Retraction of the ear drum occurs when negative pressurebuilds up in the middle ear from eustachian dysfunction. Specifically,the tube that leads from the ear to the back of the nose no longerpasses air into the middle ear. Under such conditions, a retractionpocket can form in the eardrum and eventually the pocket may turn upskin, forming a skin cyst or cholesteatoma. The entire eardrum collapsesand drapes over the bones of the middle ear. Further progression ofretraction pockets can cause erosion of the middle ear bones orossicles. While a ventilation tube is the first corrective step forretraction of the eardrum, in more severe cases a prosthesis may beneeded to replace damaged bones.

The distance where a prosthesis may be used can be anywhere from 0.5 mmto 1 mm. Existing middle ear prosthesis used for myringopexy indicationsrequire major modifications at the time of surgery. This is because thelength of the prosthesis is far too long for the distance between theeardrum and the mobile stapes. It is not uncommon that even when aprosthesis is modified, it is still too long to place between theeardrum and stapes. Additionally, existing prostheses are currently madefrom materials that are heavy or lack support.

One known prosthesis is mushroom-shaped having an enlarged head and ashaft. The current method of modifying such a prosthesis for myringopexyis to cut the shaft of the prosthesis as short as possible.Additionally, notches in the shaft may need to be added to better fitover the stapes. The current material of choice for such a prosthesis isPlasti-Pore which can be easily cut and shaped. Plasti-Pore is porouspolyethylene which permits tissue ingrowth into the interconnectingpores of the implant material. Because of the sponge likecharacteristics of Plasti-Pore, sound conduction is dampened compared tousing a more rigid material. A surgeon may also opt to use just the heador platform of a hydroxylapatite prosthesis. In such a case the shaftwhich is affixed to the hydroxylapatite head must be removed at the timeof surgery. Alternatively, the head can be sold independently.Hydroxylapatite is a ceramic based material that closely mimics naturalbone. However, weight of the material can be a concern.

The present invention is directed to improvements in a myringopexy typeprosthesis.

SUMMARY OF THE INVENTION

In accordance with the invention, there is provided a myringopexy typeprosthesis formed of a malleable body.

Broadly, there is disclosed in accordance with one aspect of theinvention, a middle ear prosthesis comprising a one piece disk shapedprosthesis comprising a generally circular malleable body including abore. The body engages a tympanic membrane and the bore receives a headof a stapes when implanted in a middle ear.

It is a feature of the invention that the bore comprises a through bore.

It is another feature of the invention that the body comprises atitanium body.

It is a further feature of the invention that the body comprises a ring,a hub and spokes connecting the ring to the hub. The hub may comprise atubular hub having opposite arch-shaped notches to align with arches ofthe stapes.

It is still another feature of the invention that the body is cannulatedon opposite sides of the bore to provide visibility of the stapes duringimplantation.

There is disclosed in accordance with another aspect of the invention amiddle ear prosthesis comprising a body comprising an annular head, acollar, and a plurality of radially extending members connecting thehead to the collar. The head engages a tympanic membrane and the collarreceives a head of a stapes when implanted in a middle ear.

It is a feature of the invention that the plurality of radiallyextending members comprise a pair of aligned, malleable radiallyextending members to enable the head to be tilted relative to thecollar.

It is another feature of the invention that diameter of the head isrelatively large compared to height of the collar.

It is still another feature of the invention that an axis of the collaris perpendicular to a plane of the head.

In accordance with another aspect of the invention, there is disclosedthe method of treating myringopexy comprising: removing an incus andmalleus of a middle ear; providing a one piece disk shaped prosthesiscomprising a generally circular malleable body including a bore;aligning the prosthesis with a stapes so a head of the stapes isreceived in the bore; and releasing a tympanic membrane so that itcollapses on the body to retain the prosthesis in the middle ear.

Further features and advantages of the invention will be readilyapparent from the specification and from the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is perspective, partial cross section view of the anatomy of anear showing a normal ossicular chain;

FIG. 2 is a view, similar to that of FIG. 1, showing the middle ear withpart of the ossicular chain removed and replaced with a prosthesis inaccordance with the invention;

FIG. 3 is a perspective view of the prosthesis in accordance with theinvention;

FIG. 4 is a plan view of the prosthesis of FIG. 3;

FIG. 5 is an elevation view of the prosthesis of FIG. 3;

FIG. 6 is a perspective view illustrating aligning the prosthesis ofFIG. 3 on a stapes;

FIG. 7 is an elevation view, similar to FIG. 5, illustrating a head ofthe prosthesis tilted relative to the collar;

FIG. 8 is a perspective view of the prosthesis of FIG. 3 with part of ahead trimmed to fit a middle ear; and

FIG. 9 is a plan view of the prosthesis of FIG. 8.

DETAILED DESCRIPTION OF THE INVENTION

Referring initially to FIG. 1, a human ear 10 includes an external orouter ear 12, a middle ear 14 and an inner ear 16. A tympanic membrane18, also called the ear drum, separates the outer ear 12 from the middleear 14. The middle ear 14 includes an ossicular chain 20 comprisingthree small bones that are connected and transmit the sound waves fromthe ear drum 18 to the inner ear 16. The three small bones are calledthe malleus 22, the incus 24, and the stapes 26. Referring to FIG. 6,the stapes 26 includes a loop or arch 28 connected to a footplate 30. Ahead 32 at the top of the arch 28 connects to the incus 24.

In accordance with the invention, a prosthesis 34 is used for treatingmyringopexy. The procedure for treating myringopexy in accordance withthe invention is for a surgeon to initially remove the incus 24 andmalleus 22. This leaves only the stapes 26 in the middle ear 14, asshown in FIG. 2. The prosthesis 34 is aligned with the stapes 26 to bereceived thereon. The tympanic membrane 18 can then be released so thatit collapses on the prosthesis 34 to retain the prosthesis 34 in themiddle ear 14.

Referring to FIGS. 3-5, the prosthesis 34 is illustrated. The prosthesis34 comprises a one piece disk shaped body 36. Particularly, the body 36comprises a generally circular malleable body including a bore 38. Thebody 36 engages the tympanic membrane 18 and the bore 38 receives thestapes head 32 when implanted in a middle ear 14. In the illustratedembodiment of the invention, the bore 38 comprises a through bore. Thebody 36 is formed of titanium. Advantageously, the body is made of asofter grade titanium, such as, for example, ASTM F67 grades 1 or 2.

More particularly, the body 36 comprises an annular ring 40 defining ahead or platform. An outer edge of the ring 40 is turned downwardly at42 to provide a smooth edge for engaging the tympanic membrane 18. Agenerally tubular collar or hub 44 defines the through bore 38. An upperedge of the hub 44 comprises a flange 46 coplanar with the ring 40. Apair of radially extending members, or spokes 48, connect the ring 40 tothe hub 44. The body is cannulated on opposite sides of the hub 44,formed by arc shaped openings 50. The tubular hub 44 includes oppositearch shaped notches 52 opposite the flange end 46.

The body 36 is approximately 3.0 mm in diameter and has a height ofapproximately 0.5 mm to provide a disk shape. The canulation provided bythe openings 50 provides maximum visibility of the stapes 26 andfootplate 30 during surgery. The malleability of the titanium enableseach side of the ring 40 to be bent and/or tilted along an axis of thespokes 48, as shown in FIG. 7 according to the patient's anatomy. Thearch cut outs or notches 52 anatomically align with the arches 28, asshown in FIG. 6. Flexibility is provided by the head design which can betrimmed such as by removing a portion of the ring 40, as shown in FIGS.8 and 9 to custom fit the patient. Titanium is considered a superiorimplant material because it weighs less than other implant materials andconducts sound vibrations well.

Referring specifically to FIGS. 2 and 6, during implantation, theprosthesis 34 is aligned with the stapes 26. The stapes head 32 isreceived in the bore 38. The notches 52 rest on the arches 28. Theopenings 50 provide visibility for the surgeon to see the arches 28 andfoot plate 30 during implantation. According to the anatomy of theparticular ear, the ring 40 can be bent, can be tilted as shown in FIG.7, or can be trimmed as shown in FIGS. 8 and 9. Further, the body 36 canbe covered with cartilage so that the tympanic membrane 18 rests on thecartilage, rather than the body 36. The body 36 floats on the cartilage,while the cartilage can grow into the tympanic membrane 18. The negativeear pressure causes the ear drum 18 to collapse onto the prosthesis 34to provide pressure contact. The tension of the tympanic membrane 18relative to the stapes head 32 sandwiches the prosthesis 34 to maintainit in position.

Thus, in accordance with the invention, there is provided a one piecedisk shaped titanium prosthesis used for treating myringopexy. Theprosthesis is designed for flexibility and stability and is lightweightand provides good sound conduction.

1. The method of treating myringopexy comprising: removing an incus andmalleus of a middle ear; providing a one piece disk shaped prosthesiscomprising a generally circular malleable body including a bore;aligning the prostheses with a stapes so a head of the stapes isreceived in the bore; and releasing a tympanic membrane so that itcollapses on the body to retain the prosthesis in the middle ear.
 2. Themethod of claim 1 wherein the body comprises a titanium body.
 3. Themethod of claim 1 wherein the body comprises a tubular hub defining thebore and the hub comprises opposite arch shaped notches and whereinaligning the prostheses with a stapes comprises positioning arches ofthe stapes in the notches.
 4. The method of claim 1 wherein the bodycomprises an annular head, a collar, and a plurality of radiallyextending members connecting the head to the collar and furthercomprising bending the radially extending members to tilt the headrelative to the collar.
 5. The method of claim 1 wherein the bodycomprises an annular head, a collar, and a plurality of radiallyextending members connecting the head to the collar and furthercomprising trimming the head to fit a middle ear.
 6. The method of claim5 wherein the body comprises an annular head, a collar, and a pluralityof radially extending members connecting the head to the collar and theplurality of radially extending members comprise a pair of aligned,malleable radially extending members to enable the head to be tiltedrelative to the collar.
 7. The method of implanting a middle earprosthesis in the absence of an incus and malleus of the middle earcomprising: providing a one piece disk shaped prosthesis comprising agenerally circular malleable body including a bore; and aligning theprostheses with a stapes so a head of the stapes is received in the boreand the tympanic membrane collapses on the body to retain the prosthesisin the middle ear.
 8. The method of claim 7 wherein the body comprises atitanium body.
 9. The method of claim 7 wherein the body comprises atubular hub defining the bore and the hub comprises opposite arch shapednotches and wherein aligning the prostheses with a stapes comprisespositioning arches of the stapes in the notches.
 10. The method of claim7 wherein the body comprises an annular head, a collar, and a pluralityof radially extending members connecting the head to the collar andfurther comprising bending the radially extending members to tilt thehead relative to the collar.
 11. The method of claim 7 wherein the bodycomprises an annular head, a collar, and a plurality of radiallyextending members connecting the head to the collar and furthercomprising trimming the head to fit a middle ear.
 12. The method ofclaim 11 wherein the body comprises an annular head, a collar, and aplurality of radially extending members connecting the head to thecollar and the plurality of radially extending members comprise a pairof aligned, malleable radially extending members to enable the head tobe tilted relative to the collar.
 13. A middle ear prosthesiscomprising: a one piece prosthesis comprising a malleable disk shapedhead and a hub disposed within the head and at least partially coplanarwith the head, the head for engaging a tympanic membrane and the hub forreceiving a head of a stapes when implanted in a middle ear, the hubbeing of a length so that a portion of the stapes head is coplanar withthe head after implantation.
 14. The middle ear prosthesis of claim 13wherein the head has a thickness of about 0.5 mm.
 15. The middle earprosthesis of claim 13 wherein the body comprises a titanium body. 16.The middle ear prosthesis of claim 13 wherein the head comprises a ringand wherein spokes connect the ring to the hub.
 17. The middle earprosthesis of claim 16 wherein the hub comprises a tubular hub havingopposite arch shaped notches to align with arches of the stapes.
 18. Themiddle ear prosthesis of claim 13 wherein the head is cannulated onopposite sides of the hub to provide visibility of the stapes duringimplantation.